The present invention relates generally to a sectional door having a support track and support rollers and, more particularly, the present invention relates to a track safety system for use with sectional doors. More particularly still, the present invention relates to a sectional door having a shield apparatus as a safety device for the rollers engaged in the support track.
Sectional doors are used in various applications such as garage doors, storage doors, and industrial doors. A sectional door typically consists of a plurality of door sections that are hinged in an edge-to-edge relationship to form the completed sectional door. The ends of each door section are supported upon support rollers, which are confined to support tracks mounted adjacent the opening of the facility, such as a garage. Each support track has a vertical section and a horizontal section with a curved section, usually as part of the horizontal track, providing transition between the vertical and horizontal direction. The vertical section of track supports the sectional door in its vertical or closed position across the opening while the horizontal section supports the sectional door in its overhead or open position. The hinges between the door sections allow the sectional door to traverse the curved section of track between the vertical and horizontal orientations.
The support track is fabricated from a strip of sheet metal that has been formed with a generally J-shaped cross section so that the support roller is constrained by the curved portion of the J-shape. The axle of the support roller extends outwardly and is anchored to the adjacent door section. The upper end of the J-shaped cross section is formed as a flange extending orthogonally from the leg of the J-shape to provide the support track with an overall cross sectional profile that is a modified C-shaped profile. The curve of the J-shape supports the roller while the flange prevents the roller from jumping the track. Dimensionally, the length of the J-shape is about 5 or 6 centimeters while the width of the curved portion of the J-shape is about 3 centimeters. The flange is larger than 3 centimeters.
A primary use of a sectional doors is in a residential setting, which typically includes children playing in and out of the garage. Children enjoy playing with things that move, but do not always appreciate the inherent dangers of the object with which they play. For example, residential sectional doors are provided with electrically driven openers to move the sectional doors between their open and closed positions. On occasion, children insert one or more fingers into the interior of the "J" shaped track during movement of the sectional door, which results in one of the support rollers either severely crushing or amputating the child's fingers. Further, the support roller has a diameter of less than 5 centimeters, which means that the angular opening between the periphery of the support roller and the support track is sufficient to receive a child's finger. The size of a child's finger coupled with the dimensions of the support roller and support track tends to pull the rest of the child's finger under the support roller during the continued rolling movement of the support roller.
One solution to guarding against fingers being inserted in a support track near the support rollers is to provide a barrier in front of the support roller. An example of such a support barrier is illustrated in Patent Cooperation Treaty Application No. PCT/DK97/00339, published Mar. 12, 1998. This reference teaches of providing a finger blocking disc, which is made of plastic, at each roller. The disc extends beyond the free edges of the support track and is designed to prevent fingers from being carelessly caught between the stationary support track and one or more of the support rollers during the opening or closing of the sectional door. The disc has a hub that is mounted with a forced fit on the shaft to which the support roller is mounted. The disc is locked in place with a locking ring. The disc also has an enlarged bead about the circumference to prevent the disc from cutting into or harming any fingers that might stray within the support track.
Unfortunately, the PCT Application No. PCT/DK97/00339 suffers from several drawbacks. One drawback is that the edge of the roller track is a cut, bare metal sheet that has a sharp edge. This sharp edge can still cut the fingers of anyone placing their hand within the support track either with or without the support rollers pinching on the fingers. Secondly, the sharp edge of the support track can also cut the fingers of someone placing their hand within the support track by the protective disc, which can easily press the fingers along or into the sharp edge of the support track. Referring now to FIG. 12 (PRIOR ART) support track 30 and roller assembly 20 are shown in the environment of a child's finger 40. Portions of curved section 32 are broken away to schematically illustrate what happens when finger 40 is placed inside support track 30 during movement of roller assembly 20. Movement of roller assembly 20 is shown schematically by movement arrow 42 that causes roller 22 to rotate as shown schematically by rotation arrow 44. This rolling action of roller 22 grips the tip of finger 40 against the inside surface of curved section 32 thereby holding finger 40 from being retracted. Continued movement of roller assembly 20 causes roller 22 to ride over finger 40 with the net effect that finger 40 is "pulled" under roller 22 as shown schematically by pulling arrow 46. Clearly, finger 40 is subjected to substantial injury by being crushed between roller 22 and the surface of J-shaped track section 32. Additionally, if finger 40 is only pushed across the exposed edge of curved section 32 finger 40 will most probably be cut by this action.
Another disadvantage with the prior art disc is that the retaining ring and the flange used to secure the protective disc on the support shaft can work loose causing the protective disc to move away from the opening in the support track. Without the protective disc guarding the support track in close proximity, fingers can get caught in the track as the door operates by being caught by the support rollers moving within the support track.
Another drawback with the disk disclosed in PCT Application No. PCT/DK97/003339 is that the disk must be sufficiently large in order for fingers not to come in contact with the support rollers during travel. This means that the disk can extend over the track portion and be broken if it is made of an inferior material. Further, children can be imaginative enough to insert something long and thin that rides in the track and is not deflected out of the track during travel. Such an item may be a stick, a toy, or the like. Failure to deflect the object could lead to a damaged track or roller, or to a stuck door that is inoperable.
Furthermore, the metal tracts in which the guide rollers travel typically have openings in them that are used for security purposes. Namely, a latch fits into one of the openings to hold the door in place. The latch can be released by a handle with a lock on it. This provides a means for locking and securing the door in a closed position. Unfortunately, a garage door opener is used in many cases to provide this security feature. Thus, the universal track with the latch openings allows a child to insert his or her fingers through the track during operation, which has been shown previously to lead to injured or severed fingers.
Accordingly, what is needed is a complete safety system for a sectional door that includes an improved protective device for shielding the support rollers and support track to prevent injury by cutting or being pinched along the support track or between the support track and the support rollers. Furthermore, what is needed is a protective device that is secured on the support shaft near the support track and support rails in such a manner as to prevent the protective disc from coming free and failing to perform the protective function desired. Also, what is needed is a support roller guide that prevents items from slipping past the protective disc and engaging with the support rollers while maintaining a fixed orientation with respect to the tract as it transitions from a horizontal to a vertical orientation and vice versa. Further, what is needed is a latch opening that is prevents penetration should no security latch be required or used with the garage door.